That's because sex was perceived specifically through a lens of power dynamics in that culture, which was not the case in several Eastern cultures at the time.

Reminds me of the line, "ain't nothing gay about gettin' your dick sucked," from the second Harold and Kumar movie.

Yeah you still have a lot of gay bros today insisting they're not gay while they fuck dude ass but that don't make it true. Maybe it was the same back then.